Roller bit



Aug. 4, 1953 Filed May 25, 1951 W. B. NOBLE ROLLER BIT 2 Sheets-Sheet l Wl/ey 5. Nob/e INVENTOR.

y jijkle n JWJ:

,4 TTOR/VEVJ Aug. 4, 1953 W. B. NOBLE ROLLER BIT Filed ma 25, 1951 2 Sheets-Sheet 2 Wz/ey 5. Nob/e INVENTOR.

A TTOHNE Yd fiatented Aug. 4, 1953 UNITED ROLLER BIT Wiley B. Noble, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application May 23, 1951, Serial N 0. 227,801

6 Claims.

This invention relates generally to roller bits for deep well drilling, and particularly to a roller bit having a new and improved bearing for the roller cutters thereof.

Conventional roller bits for the drilling of oil wells include a bit head in which are mounted roller cutters provided with teeth to penetrate the formation when the head is rotated by the usual drill stem. During drilling operations, the bearings of the roller cutters are subjected to very great shocks and strains, including destructive end thrusts. The bearings are also subjected to the abrasive action of mud-laden fluid which is pumped downwardly through the drill stem and bit and rises upwardly in the space between the drill stem and the wall of the well to keep the cutters cool, to remove the cuttings, and to perform other functions well known to those skilled in the art.

The general object of this invention is to provide a roller bit with new and improved bearings.

A specific object of the invention is to provide a roller bit with new and improved end thrust bearing rollers.

Other objects will hereinafter appear.

The preferred embodiments of the invention are illustrated by the accompanying drawings in which Fig. 1 is a partly sectional elevation'of a roller bit of the cone type; Fig. 2, a section on the line 2-2 of Fig. 1; Fig. 3, a detail view of the thrust bearing rollers and associated parts; and Fig. 4, a fragmentary sectional view illustrating a side roller cutter assembly for the conventional cross roller cutter bit.

Referring to Fig. l, the bit head is indicated at I and the roller cutters at 2. The head I is pro-. vided with a recess in its bottom defined by upwardly converging walls from which project downwardly and inwardly annular flanges, one of which is indicated at 3, providing a raceway 4 for the load sustaining bearing rollers 5. Welded as indicated at 6 in the bore 1 in the head I is a shaft 8 having an annular flange 9 and a reduced extension Ill. The extension I may provide a load sustaining friction bearing for the point of the cone, or, if desired, bearing rollers may be substituted in place of the friction bearing. The flange 9 has a reduced portion IO-a so that the shaft 8 will form with the flange 3 on the head a raceway I I for my new and improved thrust bearing rollers I5.

The thrust bearing rollers I are rotatable on axes substantially radial to the axis of rotation of the cutter 2.

As shown in detail in Figs. 2 and3, these rollers I5 include a tapered portion IE-a, a substantially cylindrical portion I 55-17 and a rounded end portion I5-c. The tapered portion I5-a may be described as frusto conical, its major diameter being substantially the same as the diameter of the cylindrical portion l5-b. The rounded portion I5-c may be a spherical segment.

The raceway I I, which may be referred to as a shaft raceway, has inwardly tapered side walls I I-a, and the tapered portions I5-a of the thrust bearing rollers I5 bear against these side walls IIa. A substantial clearance is provided between the side walls I I-a of the raceway and the tapered portions I5-a of the thrust bearing rollers I5 to permit movement of the thrust bearing rollers inwardly when the load sustaining bearing rollers 5 and pilot bearing I0 become worn. Therefore, the end thrust bearing rollers I5 sustain end thrust only. The cutter 2 is provided with a raceway I 6 and this cutter raceway I6 has substantially parallel side Walls IB-a and a rounded bottom IG-b provided with an annular groove I6-c. The cylindrical portion I5-b of the thrust bearing roller l5 bears against the parallel side walls I6-a of the cutter raceway I6, and the rounded end I5-c of the thrust bearing roller I5 bears against the rounded bottom 16-1) of the cutter raceway I5.

Within the shaft raceway I I is a ring N. This ring I! is substantially rigid so that it will prevent inward movement of the end thrust bearing rollers I5 from the circle defined by the periphery of the ring. The ring ll, however, will permit movement of the end thrust bearing rollers I5 with the ring, as a unit, transversely of the shaft, because the ring [1 floats in the shaft raceway II. Therefore, the end thrust rollers I5 do not sustain the radial load when the load bearings 5 and I0 become worn and permit movement of the cutter transversely of the shaft. The ring I! is also rotatable in the shaft raceway II. The periphery I'I-a of the ring I7 is convex as indicated to fit the concave bottoms of the end thrust rollers I5.

The parts may be assembled as follows: The shaft 8 having been placed in the cutter 2, the thrust bearing rollers may then be inserted in the cutter raceways I5. Then the ring Il may be inserted between the thrust bearing rollers I5 and the reduced portion I0-a of the flange 9 of the shaft 8. The load rollers 5 having been placed in the raceway 4 and held therein by heavy grease or the like, the cutter 2 (with the shaft 8, thrust rollers I5 and ring I? therein) may be placed over the annular flange 3 and load rollers 5, the shaft 8 entering the bore 1 and being welded in place as indicated at 6.

It will be apparent that the load on the cutter will be sustained by the bearing rollers and the friction bearing [0, and that only the end thrust will be sustained by the thrust bearing rollers [5 intermediate the same.

The bearing area between the ring l1 and the rollers i5 is a relatively large area because the engaging surfaces ll-a and l5-d (Fig. 3) of the ring and rollers are rounded. The bearing area between the ends i5-c of the rollers and the bottom iG-b of the cutter raceway it is a relatively large area because the said end and bottom are rounded. The angular groove 56-0 in the bottom of the cutter raceway l6 serves as a channel for lubricant and also as a trap for abrasive material to reduce Wear on the end 55-0 of V the roller i5.

The diameter of the thrust roller I5 is greater than its length. This results in an acute angle between the direction in which a longitudinal thrust is exerted and the direction in which that thrust is transmitted from the cutter to th shaft through the roller l5.

As will appear in Fig. 2, the tapered surfaces I5-a bear against each other and since the thrust rollers i5 rotate on axes substantially radial to the axis of rotation of the cutter 2, the tapered portions l5-a roll upon each other and thus provide a good bearing between the thrust rollers i5.

Referring now to the side roller cutter assembly shown by Fig. 4, the cross roller bit head is indicated at 20. It is provided with a downwardly and inwardly extending flange having raceways 22 for the load rollers 23. Fitting within the bore 24 of the head is a bushing 25 having an annular flange 26 and a reduced extension 2'1. The annular flange 25 on the bushing 25 forms with the annular flange ii on the head 25 a raceway 28 for my new and improved thrust bearing rollers 29. The numeral 36 indicates load rollers on the reduced extension 2'! of the bushing 25. Extending through a bore 3| in the bushing 25 is the side roller cutter pin The pin 32 is integral with and extends upwardly and outwardly from the bridge 33.

The thrust bearing rollers 29 are the same as the thrust bearing rollers 15 shown by Figs. 1, 2 and 3 and in the raceway 28 is a ring 3 5 which corresponds with the ring l'l shown by Figs. 1, 2 and 3. The side roller cutter 35 is provided with a raceway 3B which is th same as the raceway iii shown by Figs. 1, 2 and 3.

The parts shown by Fig. 4 may be assembled as follows: The bushing 25 is placed within the cutter 35. The load rollers 30 are placed between the reduced extension 21 of the bushing 25 and the cutter 35. The thrust bearing rollers 29 are then placed in the cutter raceway and the ring 34 is inserted within the circle of thrust bearing rollers 29. The load rollers 23 are placed on the raceway 22 and the cutter 35 is then placed over the rollers 23 and flange ii. The pin 32 may then be inserted through the bore 3| in the bushing 25 and welded in place as indicated at 31.

The invention is not limited to the preferred embodiments herein disclosed. Various changes within the scope of the following claims will be apparent to those skilled in the art:

I claim:

1. A bit having a shaft; a roller cutter rotatable on said shaft; said shaft having a raceway with inwardly tapered side walls, said cutter having a raceway with substantially parallel side walls and a rounded, grooved bottom; thrust bearing rollers in said raceways, rotatable on axes substantially radial to the axis of rotation of said cutter, and having tapered inner portions to bear against each other and against the tapered side Walls of said shaft raceway, said tapered inner portions being spaced radially from said tapered side Walls to provide a substantial axial space therebetween; a substantially cylindrical portion to engage the substantially parallel side walls of said cutter raceway, and a rounded end to engage .the rounded bottom of said cutter raceway; a substantially rigid ring in said shaft raceway and spaced radially therefrom to hold said rollers in the circle defined by the periphery of said ring; and load sustaining bearings on each side of said thrust bearing rollers, said ring and rollers being movable radially as a unit upon wear of said load sustaining bearings whereby said rollers are subjected to end thrust only.

2. A bit having a shaft; a roller cutter rotatable on said shaft; said shaft having a raceway with inwardly tapered side walls, said cutter having a raceway with a rounded bottom; thrust bearing rollers in said raceways, rotatable on axes substantially radial to the axis of rotation of said cutter, and having tapered inner portions to bear against each other and against the tapered side walls of said shaft raceway, said tapered inner portions being spaced radially from said tapered side walls to provide a substantial axial space therebetween, and a rounded end to engage the rounded bottom of said cutter raceway; a substantially rigid ring in said shaft raceway and spaced radially therefrom to hold said rollers in their operative positions; and load sustaining bearings on each side of said thrust bearing rollers, said ring and rollers being movable radially as a unit upon wear of said load sustaining bearings whereby said rollers are subjected to end thrust only.

3. A bit having a shaft; a roller cutter rotatable on said shaft; said shaft having a raceway with inwardly tapered side walls, said cutter having a raceway; thrust bearing rollers in said raceways, rotatable on axes substantially radial to the axis of rotation of said cutter, and having tapered inner portions to bear against each other and against the tapered side walls of said shaft raceway; said tapered inner portions being spaced radially from said tapered side walls to provide a substantial axial space therebetween; a ring in said shaft raceway and spaced radially therefrom to hold said rollers in their operative positions; and load sustaining bearings on each side of said thrust bearing rollers, said ring and rollers being movable radially as a unit upon wear of said load sustaining bearings whereby said rollers are subiected to end thrust only.

4. A bit having a shaft; a roller cutter rotatable on said shaft; said shaft having a raceway, said cutter having a raceway; thrust bearing rollers in said raceways and rotatable on axes substantially radial to the axis of rotation of said cutter; a ring floating in said shaft raceway to hold said rollers exteriorly thereof in their operative positions; and load sustaining bearings on each side of said thrust bearing rollers, said ring being spaced from said shaft to permit transverse movement thereof as said load sustaining bearings wear.

5. A bit having a shaft, a roller cutter rotatable on said shaft, said shaft and cutter having raceways, one of said raceways having tapered side walls,. thrust bearing rollers in said raceways,

said rollers being rotatable on axes substantially radial to the axis of rotation of said cutter and having tapered portions bearing against each other and against the said tapered side walls of said raceway, and a ring floating in said shaft raceway and spaced radially therefrom to hold said rollers in their operative positions in said raceways while permitting transverse movement of said rollers and ring relative to said shaft.

6. A bit having a shaft, a roller cutter rotatable on said shaft, raceways in said shaft and cutter, and an end thrust bearing unit in said raceways, said unit including a ring and end thrust bearing rollers rotatable on said ring on axes substantially radial to the axis of rotation of said cutter, said ring being disposed between said rollers and said shaft raceway, and said unit being movable transversely of the axis of said shaft.

WILEY B. NOBLE.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 1,106,065 2,004,012 2,065,740 2,075,999 2,210,077 10 2,293,603 2,490,151

Number 10 57,196 

